Richard A. Feely, Ph.D. NOAA Pacific Marine Environmental Laboratory/NOAA NOAA Ocean Climate Climate Observation 7 th Annual System Review 28 October 2008 Developing an Ocean Acidification Observing Network to Study the Other CO 2 Problem PMEL PIs: R. Feely, C. Sabine S. Alin, L. Juranek, A. Sutton, S. Hankin AOML PIs: R. Wanninkhof, T.-H. Peng, D. Gledhill, D. Manzello, J.-Z. Zhang University PIs: U. Send (SIO), A. Dickson (SIO), B. Hales (OSU), J. Salisbury (UNH), S. Lohrenz (USM), W. Cai (UG) J. Salisbury (UNH), S. Lohrenz (USM), W. Cai (UG)

Conceptual Diagram of Ocean Acidification

Ocean CO 2 Chemistry Ocean Acidification 2− [CO 3 ] [CO 2 ]  150−200%  50% pH μmol kg −1 Year pH CO 2(aq) CO 3 2−  50% acidity  16% [CO 3 ] − Wolf-Gladrow et al. (1999)

Ocean CO 2 Chemistry Saturation State calciumcarbonate calcium carbonate Saturation State  phase  Ca 2   CO 3 2   K sp,phase *  1  precipitation  1  equilibrium  1  dissolution

Change in Aragonite Saturation with CO 2 Steinacher et al. Biogeosci., Saturation state declines across all latitudes -Undersaturated conditions appear for aragonite in high latitudes

WOCE/JGOFS/OACES Global CO 2 Survey ~72,000 sample locations collected in the 1990s DIC ± 2 µmol kg -1 TA ± 4 µmol kg -1 Sabine et al (2004) 2005/2006, 1991

 Difference of present-day levels minus pre- industrial (year 1800)  Half trapped in upper 400m  Equivalent to about a third of all historical carbon emissions Penetration of Anthropogenic CO 2 into Ocean Sabine et al. Science 2004

Ocean CO 2 Chemistry Observed aragonite & calcite saturation depths Feely et al. (2004) The aragonite saturation state migrates towards the surface at the rate of 1-2 m yr -1, depending on location.

DIC change due to ventilation and respiration processes Total DIC change over 15 years in the Pacific Sabine et al. (in prep) DIC change due to uptake of anthropogenic CO 2

Shoaling of aragonite saturation horizon of ~1-2 m yr -1 Large-scale decreases of aragonite saturation in the upper 1000m Feely et al. (in prep) Δ Saturation Depth (m)

“The further development of current biogeochemical sensors and the development of new sensors is critical to the ongoing development of an integrated ocean observing system. Reliable sensors for autonomous platforms is an important research and development focus for pCO 2 and other carbon sensors including DIC and total alkalinity. These sensors along with certified reference material would enable the ocean carbonate system to be constrained.”

An International Ocean Acidification Observing Network

from Feely et al., 2010

Ocean acidification Ocean Carbon Observatory Network Updated 10/5/10

Coastal Moorings Operated by SIO All real-time, with meteorological, physical, chemical, and biological variables CCE1 CCE2 Del Mar

California Current Ecosystem (CCE) moorings Pt.Conception Gliders (CORC, LTER, Moore) CalCOFI/ LTER CCE-1 (SIO/ SWFSC/PMEL) The power of CCE1/2 comes from the context of other measurements - Ships sample many variables and provide ground truth - Gliders provide cross-shelf sampling with a few variables - Moorings give full time sampling, wide range of variables CalCOFI line 80 CCE-2 (SIO/ SWFSC/PMEL) Chlorophyll shown on surface; salinity on cross-section

CCE-2 Real-time data example Send & Ohman with Demer, Martz, Sabine, Feely, Dickson, Hildebrand upwelling

SBE-37 Durafet ISE Reference Aanderaa 3835 Optode SBE 5M pump Flow manifold Copper intake

CCE-1 surface pH (Jan – Sept. 2010) Figure provided by T. Martz, U. Send, M. Ohman, SIO Figure provided by T. Martz, U. Send, M. Ohman, SIO pH measured using a modified Honeywell Durafet and estimated from pCO 2 using TA = f(S,T) provided by Simone Alin (PMEL). Examining the agreement between the three different pH values provides a useful QC on sensor data.

An Ocean Acidification Observing Network What tools do we need to address ocean acidification?

Autonomous Underwater Gliders Innovating Technology High resolution data J. Barth, K. Shearman & A. Erofeev CTD dissolved oxygen chlorophyll fluorescence CDOM fluorescence light backscatter cross-margin transect twice per week since April 2006

Algorithms to predict Ω arag and pH in the N. Pacific Juranek, Feely et al. (in prep) Algorithm development data: CLIVAR P16 (March, 2006) STUD08 (Sept., 2008) Data from 40-55°N, db: Ωarag: R 2 =0.99, RMSE=0.05 pH: R 2 =0.99, RMSE=0.017

Conclusion Conclusions and Challenges Since the beginning of the industrial age surface ocean pH (~0.1), carbonate ion concentrations (~16%), and aragonite and calcite saturation states (~16%) have been decreasing because of the uptake of anthropogenic CO 2 by the oceans, i.e., ocean acidification. By the end of this century pH could have a further decrease by as much as pH units. An observational network of repeat surveys, moorings, floats and gliders for ocean acidification is under development as a strong collaboration between federal, state and private institutions using state-of-the-art technologies and new proxies. Special Thanks to: Joan Kleypas, Uve Send, Sarah Cooley, and Scott Doney. Near real-time data transmission and uniform data management infrastructure is required with public availability. Moored and glider sensors for Dissolved Inorganic Carbon, Total Alkalinity and pH need development. Near real-time data transmission and uniform data management infrastructure is required with public availability.